Effects of dietary SID valine : lysine ratios in lactating sows on nutrient utilization and growth of piglets

This study was conducted to evaluate the effects of standardized ileal digestible (SID) valine : lysine (Val : Lys) ratio on the performance, body composition, and nutrient digestibility of lactating sows and their piglets.Twenty pregnant sows of a three-way crossbreed [(Landrace × Yorkshire) × Duroc] at parity 2 -3 [(initial body weight (BW) of 219.00 ± 4.81 kg)] were assigned to four dietary treatments with SID Val : Lys ratios of 69%, 83%, 103%, and 123%.Each treatment contained five replicates with one sow per replicate.Sows were fed the respective diets from d 110 of gestation through d 21 of lactation.Weaning piglets were fed the common basal diets for 5 weeks to evaluate the carry-over effects of maternal SID Val : Lys ratios on post-weaning growth.Measurements included sow average daily feed intake (ADFI), BW loss, backfat thickness, reproductive performance, piglet body weight gain (BWG), and nutrient digestibility (dry matter, crude protein, and gross energy).Results showed no significant differences among treatment groups in ADFI, litter size, number of weaning piglets, piglet mortality, backfat thickness loss, birth weight, or nutrient digestibility (p > 0.05).However, the 69% SID Val : Lys treatment resulted in significantly greater BW loss in sows compared to the 83% and 103% treatments (p < 0.05).Additionally, piglet BW at d 21 and 56 were significantly lower in the 69% treatment compared to the 83% and 103% treatments (p < 0.05).Therefore, an SID Val : Lys ratio of 83 to 103% in lactating sow diets is recommended as the optimal range to maintain sow body composition and enhance piglet growth performance.